EP0924500B1 - Method for the measurement of electromagnetic radiation - Google Patents

Method for the measurement of electromagnetic radiation Download PDF

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Publication number
EP0924500B1
EP0924500B1 EP98123129A EP98123129A EP0924500B1 EP 0924500 B1 EP0924500 B1 EP 0924500B1 EP 98123129 A EP98123129 A EP 98123129A EP 98123129 A EP98123129 A EP 98123129A EP 0924500 B1 EP0924500 B1 EP 0924500B1
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EP
European Patent Office
Prior art keywords
radiation
modulation
lamp
detector
lamps
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EP98123129A
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German (de)
French (fr)
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EP0924500A2 (en
EP0924500A3 (en
Inventor
Markus Hauf
Thomas Knarr
Heinrich Walk
Horst Balthasar
Uwe Müller
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Steag RTP Systems GmbH
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Steag RTP Systems GmbH
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Priority claimed from DE19855683A external-priority patent/DE19855683A1/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/0003—Radiation pyrometry, e.g. infrared or optical thermometry for sensing the radiant heat transfer of samples, e.g. emittance meter

Definitions

  • the invention relates to a method for measuring electromagnetic radiation emitted from a surface of an object.
  • the electromagnetic radiation to be measured is radiated from a surface of an object which is irradiated by electromagnetic, emitted by at least one radiation source electromagnetic radiation, wherein the radiation emitted by the radiation source with at least one first radiation detector and the radiation emitted by the irradiated object radiation is determined with at least one second radiation detector.
  • the radiation emitted by at least one radiation source is actively modulated with at least one characteristic parameter, and the radiation detected by the second radiation detector is corrected for compensation of the radiation of the radiation source reflected by the object by the radiation determined by the first radiation detector.
  • a another method for measuring an electromagnetic radiation radiated from a surface of an article is known. Means are provided to modulate the intensity of the radiation provided by the radiation source. One detector measures the radiation intensity emitted by the object, while another detector measures the radiation emitted directly by the radiation source.
  • DE-A-26 27 753 shows a device for measuring and controlling the thickness of optically active thin films during their construction in vacuum coating systems.
  • the measurement and control is achieved by detecting the reflection or transmission behavior of layer thicknesses between fractions and a few multiples of the wavelength of the used, substantially monochromatic measurement light and by interrupting the coating process when a predetermined layer thickness is reached.
  • the device consists of a measuring light source for a focused measuring light beam, a chopping device, a beam splitter arranged at an angle of 45 ° in the axis of the measuring light beam, a measuring light receiver with monochromator connected upstream, and a differentiation device for the measuring signal and an interrupting device for the coating process.
  • DE-A-42 24 435 describes an optical interface for the infrared surveillance of transparent panes, in which the light of an infrared radiation source is guided by optical waveguides into the interior of the interface and emitted there to expose the pane surface.
  • the radiation reflected at the disc to be monitored is received by the entrance of another optical waveguide and passed through the optical waveguide via a daylight filter onto a photodetector.
  • US-A-5 270 222 shows a method and an apparatus for a diagnosis and prognosis in the manufacture of semiconductor devices.
  • the device has a sensor for diagnosis and prognosis, which measures different optical properties of a semiconductor wafer.
  • the sensor includes a sensor arm and an optoelectronic control box for directing coherent electromagnetic or optical energy toward the semiconductor wafer.
  • the invention is therefore based on the object to provide a method of the type mentioned, with which the measurement of electromagnetic radiation and the determination of the derived parameters and values can be performed in a simple manner even more accurate.
  • a non-periodic modulation can be z. B. is obtained by linking the characteristic parameter to a positive or negative increment generated by a random mechanism via a linking operation (eg, addition, multiplication, or linkage to a look-up table).
  • the increment is determined after a time interval each new according to a random principle.
  • the time interval itself can be determined constantly, according to a predefined function or again according to a random principle.
  • the parameters determined by random principles are known and available within an evaluation device or an evaluation method for signal analysis.
  • the parameters determined by a random principle can satisfy any predefined distribution function. You can z. B. be equal, Gaussian or poissonverteil be whereby the respective expected values of the parameters are also predefined.
  • the advantage of non-periodic modulation is that it can suppress periodic disturbances.
  • the radiation source is preferably a heating lamp and the irradiated article is preferably a semiconductor substrate which is subjected to a thermal treatment.
  • the active modulation of the radiation emitted by the radiation source is used for its characterization in the correction of the radiation detected by the second radiation detector. Due to the active and thus known modulation of the radiation emitted by the radiation source, the characterization and thus differentiation of this radiation from the actual radiation to be measured, which is emitted by the object, is particularly simple, reliable and quantitatively accurate.
  • the radiation emitted by the radiation source is preferably amplitude, frequency and / or phase modulated.
  • the choice of the type of modulation is selectable, the modulation type in particular with regard to the simplicity and reliability of the modulation method, but also the evaluation process and the detection method is selectable.
  • Amplitude modulation is to be understood as the modulation of the modulation amplitude. Preferably, however, working with intensity modulation whose amplitude is not modulated, but may vary slowly.
  • each waveform of the modulation it is also possible to use each waveform of the modulation.
  • a signal waveform with the signal curve that is as steady as possible is used. This has the advantage that even with a Fourier transformation high frequencies essentially do not occur and therefore the number of samples per unit of time in the detection or processing of the detected signal can remain low, so that a good evaluation method nevertheless provides a good and accurate measurement is feasible.
  • a further advantageous embodiment of the invention is that the radiation source consists of a plurality of individual radiation sources, for example of a plurality of lamps, which can be combined to form one or more lamp banks.
  • at least one of the lamps is modulated in their radiation.
  • the modulation of the radiation of a lamp to achieve the advantages of the method according to the invention may be sufficient, although the modulation of only one lamp only makes a meaningful result under restrictions to the universality of the measuring method.
  • a particularly simple control of the lamps with a single circuit breaker is given in particular even if at least two lamps or all lamps are modulated in terms of their radiation in the same manner.
  • the modulation of the radiation of only one or a few lamps to avoid unwanted reflections.
  • the radiation modulation of the individual lamps or radiation sources is preferably for at least some of they are temporally synchronous or provided in a fixed temporal relationship to each other, although temporally non-synchronous beam modulations may be advantageous in certain applications.
  • the degree of modulation and in particular the modulation depth of the radiation emitted by the radiation source possibly also different from radiation source to radiation source - independent of the radiated lamp intensity.
  • This so-called absolute modulation is thus independent of the base level or DC signal with which the radiation source or lamp is driven.
  • This embodiment of the invention has the advantage that during the increase in the intensity of the radiation source, which should optionally be made quickly, the full drive can be exploited and is not limited by an excessive modulation in their intensity.
  • the embodiment of the invention is more advantageous, in which the degree of modulation or the depth of modulation depends on the radiated intensity of the radiation source.
  • This so-called relative modulation in which, for example, the magnitude of the AC drive signal depends on or is proportional to the intensity of the DC drive signal of the radiation source, has the advantage that the relative modulation degree is constant or changes only to a lesser extent, whereby the Detection of the modulation and evaluation is easier and less expensive devices feasible.
  • the degree of modulation or the depth of modulation is controlled or actively regulated.
  • the lamp intensity and / or the modulation itself is pulse-width-modulated.
  • the radiation of the radiation source is modulated by using table values with a data processing program.
  • Another very advantageous embodiment of the invention is also to modulate the radiation by changing the counter frequency of generators for the pulse width modulation.
  • the lamp power is changed by pulse width modulation.
  • the radiation intensity is a function of the spiral temperature, which however corresponds directly to the lamp power in the stationary, steady state.
  • the radiation of the radiation source is preferably modulated by a modulation of the drive signal or the drive signals for the radiation source or the lamps.
  • the point at which the drive signal is modulated within the signal generation depending on the needs and circumstances selectable. It is particularly advantageous if the drive signal is modulated immediately after its generation before being fed to the radiation source or the lamps.
  • the present invention is of great advantage for determining the temperature, reflectivity and / or emissivity of an article applicable, for example in connection with a device for the thermal treatment of substrates such as in an oven, in which the substrates are fast and with the most accurate, predetermined temperature profile be heated and cooled.
  • the radiation emitted by at least one radiation source for example a heating lamp
  • the radiation originating from the object to be heated are determined, the latter being composed of the radiation emitted by the object and the radiation reflected by the object.
  • the amplitudes of the modulated components are proportioned as measured by the radiation detector provided for the article and the radiation detector provided for the radiation sources.
  • the resulting from the amplitude ratio number is proportional to the reflectivity of the object, for example, the wafer in a first approximation.
  • This number will now be used twice for further evaluation. First, it is used to distinguish the radiation emitted by the object, ie the heat radiation of the object from the radiation of the radiation source reflected by the object. Secondly, this number is used to scale back the radiation emitted by the object, ie the thermal radiation, back to the radiation of a black body of the same temperature.
  • the first detector is a radiation detector which measures in a simple and reliable manner the radiation emitted by the radiation source.
  • the radiation emitted by the radiation source is advantageously conducted via optical lines or light channels to the radiation detector.
  • the radiation sources and the optical conduits or light channels are arranged relative to one another such that the first radiation detector generates a signal which is free of influences from filament holders or other means interfering with the radiation flux or radiation temperature of the radiation source.
  • the first detector a temperature sensor, such.
  • a thermocouple with which the lamp temperature and thus the radiated intensity can be determined.
  • the first detector measures any parameter related to the radiation emitted by the radiation source.
  • the intensity may be determined via an impedance measuring device that measures the impedance (eg, the ohmic resistance) of a lamp filament.
  • impedance measuring device that measures the impedance (eg, the ohmic resistance) of a lamp filament.
  • a suitable processing unit knowing the impedance-intensity relation of the radiation source, such as B. a heating lamp whose radiated intensity or a proportional thereto parameters are determined.
  • reaction chamber 1 and 2 shows a preferably quartz glass reaction chamber 1 with a semiconductor wafer 2 located therein.
  • the reaction chamber 1 is surrounded by a housing 3, which has lamps 4, 5 at the top and bottom, respectively has, whose radiation is directed to the reaction chamber 1.
  • the reaction chamber 1 consists essentially of a substantially transparent to the lamp radiation material, which is also transparent with respect to the measuring wavelengths or the Meßwelleninspektren the pyrometer or the radiation detectors used.
  • quartz glasses and / or sapphire which has an averaged absorption coefficient over the lamp spectrum from about 0.1 1 / cm to 0.001 1 / cm
  • suitable reaction chambers for rapid heating systems can be constructed in which the thickness of the reaction chamber wall can be between 1 mm and several centimeters, for example 5 cm.
  • the choice of material can be made with regard to the absorption coefficient.
  • Chamber thicknesses in the centimeter range are particularly necessary if in the reaction chamber 1, a negative pressure (up to the ultra-high vacuum) or an overpressure to be generated. If, for example, the reaction chamber diameter is about 300 mm, a sufficient mechanical stability of the chamber 1 is obtained with a quartz glass thickness of about 12 mm to 20 mm, so that it can be evacuated.
  • the reaction chamber wall thickness is dimensioned according to the wall material, the chamber size and the pressure loads.
  • a schematically represented pyrometer 6 (cf., in particular, FIG. 2) with a large entrance angle measures the radiation emitted by the semiconductor wafer 2 and the radiation of the lamps 5 reflected at the semiconductor wafer 2, which lamps are designed as flashlights in the illustrated embodiment.
  • An arrangement of this type is known and described for example in DE 44 37 361 C or the non-prepublished DE 197 37 802 A the same applicant, so that reference is made to avoid repetition, and these documents are made insofar as the content of the present description ,
  • the filament at least partially have a helical structure.
  • the filament of the lamp z. B. alternately coiled and uncoiled filament sections.
  • the radiation profile (both the geometric and the spectral) is determined in this case essentially by the distance between adjacent coiled filament sections.
  • Another way to define the Lampenabstrahlprofil consists z. In that the density of the filament structure (eg, the filament density) is varied along the filament.
  • lamps preferably flashlights
  • Lamps with controllable lamp profile are particularly in fast heating systems for heat treatment of large-area substrates such.
  • As 300mm semiconductor wafer advantageous because can be achieved along the substrate surface with these lamps and a suitable Lampenan Kunststoffvorraum a very homogeneous temperature profile.
  • the superposition of the individual emission profiles of the filaments results in an overall radiation profile of the lamp which can be set in a wide range. In the simplest case, z. As a halogen lamp two filaments, z. B.
  • a further embodiment possibility of a lamp with controllable emission profile is that the filament of the lamp comprises at least three electrical connections, wherein in each case different operating voltages are applied between the terminals. This can be done sections, the filament temperature, and thus control the radiation characteristics of the lamp, along the filament.
  • the emission profile also being adjustable here.
  • the lamp spectrum can be adjusted via the current density from the UV range to the near infrared.
  • the arc lamps have the advantage in terms of active modulation that they can be operated at a higher modulation frequency. This simplifies both the signal processing electronics and the evaluation.
  • Another pyrometer 7 receives via optical lines or light channels 8, the light emitted by the lamps 5 directly supplied.
  • the radiation sources and / or the light channels are preferably arranged such that the lamp pyrometer signal results from a lamp or filament section which is free of filament holding devices or other means interfering with the radiation flux or the temperature of the filament or lamp section observed through the light channels.
  • the output signals of the pyrometer 6 and 7 are supplied to an evaluation circuit, not shown, which detects the radiation emitted by the semiconductor wafer 2 by the fact that it sets the radiation falling on the pyrometer 6 with the radiation detected by the pyrometer 7 in relation and thereby determines the radiation from Semiconductor wafer 2 is emitted. This is possible because the radiation emitted by the lamps 5 is actively and modulated in a defined manner.
  • This modulation is also contained in the radiation received by the wafer pyrometer 6, so that by comparison or in relationship sets of modulation depths or modulation depths of the radiation received by the pyrometers 6 and 7 compensation of reflected from the semiconductor wafer 2 lamp radiation in the field captured by the wafer pyrometer 6 radiation is possible, and thereby the radiation emitted by the semiconductor wafer 2 and thus its temperature, reflectivity, transmissivity and / or emissivity can be measured accurately.
  • a further, corresponding lamp pyrometer as shown in FIGS. 1 and 2 and described above, according to a further embodiment may also be provided with corresponding light pipes or shafts on the other side of the housing 3 for measuring the lamp radiation of the upper lamps 4.
  • the upper lamp pyrometer corresponds in its function to that of the lower lamp pyrometer 7 in that the upper lamp pyrometer measures the radiation and its intensity with respect to the upper lamps 4. It is particularly advantageous if the type of modulation or the degree of modulation of the lamps of the upper bank of lamps is different from the degree of modulation or the modulation of the lower bank of lamps.
  • the intensities I of the radiation sources are plotted over time.
  • the degree of modulation or the depth of modulation is essentially constant and independent of the radiation intensity emitted by the radiation source, while in the example shown in FIG. 3b the degree of modulation or the depth of modulation depends on the radiated intensity of the radiation source or the size its drive signal depends or is proportional to her.
  • the so-called absolute modulation according to FIG. 3a has the advantage that, during the high heating of the semiconductor wafer 2 or the reaction chamber 1, the heating power is practically unaffected by the modulation, and therefore the entire intensity for the rapid heating is available.
  • the so-called relative modulation according to FIG. 3b has the advantage of having the degree of modulation or the depth of modulation all the more, the higher the radiation power of the radiation sources. Controlling or actively controlling the modulation depth is also possible.
  • Fig. 4 is a schematic circuit arrangement for controlling a radiation source or lamps 11 for generating a radiation or a radiation profile for a certain wafer temperature or a specific temperature profile is shown, heated by the wafer 2 or by appropriately switching off or reducing the intensity of the Lamps should be cooled.
  • a comparator 11 the indirectly measured with the wafer pyrometer 6 wafer temperature (terminal 13) is compared with a target temperature 14 and the comparison signal fed to a controller 15, at whose output the drive signal corresponding to the adjusting elements 16, 17 on the two lamps or Divided lamp banks becomes. Thereafter, the drive signal is divided by splitter 18, 19 on the individual lamps 4, 5 of the lamp banks, wherein for the sake of clarity, only one splitter 18, 19 is shown concretely, which emits the drive signal to the lamp 4 and 5 respectively.
  • the drive signal is modulated immediately in front of the lamp 4 or 5, since in this way distortions which could be caused by the lamp drive circuit can be avoided.
  • the modulation is thus carried out at the circuit point 20 or 21 by means not shown modulation means, for example by programmable curves, amplitude and / or Frequensverstructure.
  • the modulation can also be made at other locations within the drive circuit according to FIG. 4, for example at the circuit point 22 or at the circuit point 20 before or after the controller 23. In this case, however, an individual modulation of the drive signals for each lamp is not possible because the modulation of the common output signal is uniform.
  • the modulation can be carried out in a simple manner by means of a corresponding data processing program.
  • Software tables allow virtually all waveforms and frequencies to be freely programmed, with the length of the table determining the frequency since the table can be processed with a fixed time base (for example 1 ms) and can be repeated as often as desired after reaching the end of the table.
  • C mod is the degree of modulation
  • C DC is the value of the unmodulated or fundamental intensity or amplitude
  • T (n) are the respective discrete table values.
  • any modulation degrees or depths, waveforms and frequencies can be easily programmed.
  • the discrete table values result 256, 435, 512, 435, 256, 76, O, 76.
  • the average value of the table values must be equal to the divisor, so that the resulting integrated power remains unchanged.
  • the resolution, d. H. the number of table values per time unit can be changed by taking a different basis.
  • This driving or modulation method has the advantage that only shift and multiply instructions are required when the divisor is a base 2 number.
  • the method according to the invention is in particular also associated with devices or measuring methods other than those described above can be used with advantage in order to obtain reliable, reproducible measurement results with simple means and to determine therefrom the temperature, the transmissivity, the emissivity and / or the reflectivity of objects with high accuracy.
  • the method according to the invention can also be used with other detectors than the illustrated and described lamp pyrometer. So z. B. instead of the lamp pyrometer, a temperature sensor, such. B. a thermocouple can be used to determine the emitted radiation from the lamps.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Radiation Pyrometers (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)

Description

Die Erfindung betrifft ein Verfahren zum Messen elektromagnetischer Strahlung, die von einer Oberfläche eines Gegenstands abgestrahlt wird.The invention relates to a method for measuring electromagnetic radiation emitted from a surface of an object.

Aus der EP 0 539 984 A2 ist ein derartiges Verfahren bekannt, bei dem die zu messende elektromagnetische Strahlung von einer Oberfläche eines Gegenstands abgestrahlt wird, der durch elektromagnetische, von wenigstens einer Strahlungsquelle abgegebenen elektromagnetischen Strahlung bestrahlt wird, wobei die von der Strahlungsquelle abgegebene Strahlung mit wenigstens einem ersten Strahlungsdetektor und die vom bestrahlten Gegenstand abgegebene Strahlung mit wenigstens einem zweiten Strahlungsdetektor ermittelt wird. Die von wenigstens einer Strahlungsquelle abgegebene Strahlung wird mit wenigstens einem charakteristischen Parameter aktiv moduliert, und die vom zweiten Strahlungsdetektor ermittelte Strahlung wird zur Kompensation der vom Gegenstand reflektierten Strahlung der Strahlungsquelle durch die vom ersten Strahlungsdetektor ermittelte Strahlung korrigiert.From EP 0 539 984 A2, such a method is known, in which the electromagnetic radiation to be measured is radiated from a surface of an object which is irradiated by electromagnetic, emitted by at least one radiation source electromagnetic radiation, wherein the radiation emitted by the radiation source with at least one first radiation detector and the radiation emitted by the irradiated object radiation is determined with at least one second radiation detector. The radiation emitted by at least one radiation source is actively modulated with at least one characteristic parameter, and the radiation detected by the second radiation detector is corrected for compensation of the radiation of the radiation source reflected by the object by the radiation determined by the first radiation detector.

Aus der WO 94/00744 A ist ein weiteres Verfahren zum Messen einer von einer Oberfläche eines Gegenstandes abgestrahlten elektromagnetischen Strahlungbekannt. Einrichtungen sind vorgesehen, um die Intensität der von der Strahlungsquelle bereitgestellten Strahlung zu modulieren. Ein Detektor misst die vom Gegenstand abgestrahlte Strahlungsintensität, während ein weiterer Detektor die von der Strahlungsquelle direkt abgegebene Strahlung misst.From WO 94/00744 A another method for measuring an electromagnetic radiation radiated from a surface of an article is known. Means are provided to modulate the intensity of the radiation provided by the radiation source. One detector measures the radiation intensity emitted by the object, while another detector measures the radiation emitted directly by the radiation source.

Ein weiteres Verfahren ist beispielsweise aus der US-5 490 728 A im Zusammenhang mit der Fertigung von Halbleitersubstraten in einer Reaktionskammer bekannt. Die von der Strahlungsquelle abgegebene elektromagnetische Strahlung ist dabei naturgemäß mit einer Welligkeit überlagert, die durch Schwankungen der Netzspannung oder auf Grund von Phasen-Anschnittssteuerungen ungewollt auftreten. Auf diese Welligkeit kann jedoch kein Einfluss genommen werden, und sie kann auch nicht bewusst gewählt werden. Sie ist daher für eine bewusste Ausnutzung als Charakteristik der von der Strahlungsquelle abgegebenen Strahlung - wenn überhaupt - nur bedingt tauglich.Another method is known, for example, from US Pat. No. 5,490,728 A in connection with the production of semiconductor substrates in a reaction chamber. The emitted from the radiation source electromagnetic Radiation is naturally superimposed with a ripple, which unintentionally occur due to fluctuations in the mains voltage or due to phase-gating controls. However, this ripple can not be influenced, and it can not be consciously chosen. It is therefore only conditionally suitable for conscious utilization as a characteristic of the radiation emitted by the radiation source, if at all.

Ferner sei auf die DE-A-26 27 753 verwiesen, welche eine Vorrichtung zur Dickenmessung und -steuerung optisch wirksamer Dünnschichten während ihres Aufbaus in Vakuumbeschichtungsanlagen zeigt. Die Messung und Steuerung wird erreicht durch Erfassen des Reflexions bzw. Transmissionsverhaltens von Schichtdicken zwischen Bruchteilen und einigen Vielfachen der Wellenlänge des verwendeten, im wesentlichen monochromatischen Messlichts und durch Unterbrechung des Beschichtungsvorgangs bei Erreichen einer vorbestimmten Schichtdicke. Die Vorrichtung besteht aus einer Messlichtquelle für einen fokussierten Messlichtstrahl, eine Zerhackervorrichtung, einen in der Achse des Messlichtstrahls unter einem Winkel von 45° angeordneten Strahlenteiler, einem Messlichtempfänger mit vorgeschaltetem Monochromator, sowie aus einer Differenziereinrichtung für das Messsignal und einer Unterbrechungseinrichtung für den Beschichtungsvorgang. Darüber hinaus ist in der DE-A-42 24 435 ein optisches Interface für die Infrarotüberwachung von Klarsichtscheiben beschrieben, bei dem das Licht einer Infrarotstrahlungsquelle durch Lichtwellenleiter ins Innere des Interface geleitet und dort zum Belichten der Scheibenoberfläche ausgestrahlt wird. Die an der zu überwachenden Scheibe reflektierte Strahlung wird durch den Eingang eines anderen Lichtwellenleiters aufgenommen und durch den Lichtwellenleiter über einen Tageslichtfilter auf einen Photodetektor geleitet. Weiterhin zeigt die US-A-5 270 222 ein Verfahren und eine Vorrichtung für eine Diagnose und Prognose bei der Herstellung von Halbleitervorrichtungen. Die Vorrichtung weist einen Sensor für die Diagnose und Prognose auf, der unterschiedliche optische Eigenschaften eines Halbleiterwafers misst. Der Sensor weist einen Sensorarm und einen optoelektronische Steuerbox auf, zum Leiten kohärenter elektromagnetischer oder optischer Energie in Richtung des Halbleiterwafers.Further reference is made to DE-A-26 27 753, which shows a device for measuring and controlling the thickness of optically active thin films during their construction in vacuum coating systems. The measurement and control is achieved by detecting the reflection or transmission behavior of layer thicknesses between fractions and a few multiples of the wavelength of the used, substantially monochromatic measurement light and by interrupting the coating process when a predetermined layer thickness is reached. The device consists of a measuring light source for a focused measuring light beam, a chopping device, a beam splitter arranged at an angle of 45 ° in the axis of the measuring light beam, a measuring light receiver with monochromator connected upstream, and a differentiation device for the measuring signal and an interrupting device for the coating process. Moreover, DE-A-42 24 435 describes an optical interface for the infrared surveillance of transparent panes, in which the light of an infrared radiation source is guided by optical waveguides into the interior of the interface and emitted there to expose the pane surface. The radiation reflected at the disc to be monitored is received by the entrance of another optical waveguide and passed through the optical waveguide via a daylight filter onto a photodetector. Furthermore, US-A-5 270 222 shows a method and an apparatus for a diagnosis and prognosis in the manufacture of semiconductor devices. The device has a sensor for diagnosis and prognosis, which measures different optical properties of a semiconductor wafer. The sensor includes a sensor arm and an optoelectronic control box for directing coherent electromagnetic or optical energy toward the semiconductor wafer.

Der Erfindung liegt daher die Aufgabe zugrunde, ein Verfahren der eingangs genannten Art zu schaffen, mit dem die Messung elektromagnetischer Strahlung und die Ermittlung der daraus abgeleiteten Parameter und Werte auf einfache Weise noch genauer durchgeführt werden kann.The invention is therefore based on the object to provide a method of the type mentioned, with which the measurement of electromagnetic radiation and the determination of the derived parameters and values can be performed in a simple manner even more accurate.

Die gestellte Aufgabe wird erfindungsgemäß durch das in Anspruch 1 angegebene Verfahren gelöst. Vorteilhafte Ausführungsformen sind in den abhängigen Ansprüchen beansprucht.The stated object is achieved by the method specified in claim 1. Advantageous embodiments are claimed in the dependent claims.

Eine nichtperiodische Modulation lässt sich z. B. dadurch erhalten, dass der charakteristische Parameter mit einem positiven oder negativen Inkrement, das mittels eines Zufallsmechanismus erzeugt wird, über eine Verknüpfungsoperation (z. B. Addition, Multiplikation oder einer Verknüpfung mit einer Look-up-Tabelle) verknüpft wird. Dabei wird das Inkrement nach Ablauf eines Zeitintervalls jeweils neu nach einem Zufallsprinzip bestimmt. Das Zeitintervall selbst kann dabei konstant, nach einer vordefinierten Funktion oder wiederum nach einem Zufallsprinzip bestimmt werden. Wichtig bei der nichtperiodischen Modulation ist, dass die durch Zufallsprinzipien bestimmten Parameter (Inkrement und/oder Zeitintervall) bekannt und innerhalb einer Auswertevorrichtung oder eines Auswerteverfahrens zur Signalanalyse zu Verfügung stehen. Die durch ein Zufallsprinzip bestimmten Parameter (Inkrement und/oder Zeitintervall) können einer beliebig vordefinierten Verteilungsfunktion genügen. Sie können z. B. gleich-, gauß- oder poissonverteilt sein, wodurch die jeweiligen Erwartungswerte der Parameter ebenfalls vordefiniert sind. Der Vorteil einer nichtperiodischen Modulation liegt darin, dass dadurch periodische Störeinflüsse unterdrückt werden können.A non-periodic modulation can be z. B. is obtained by linking the characteristic parameter to a positive or negative increment generated by a random mechanism via a linking operation (eg, addition, multiplication, or linkage to a look-up table). In this case, the increment is determined after a time interval each new according to a random principle. The time interval itself can be determined constantly, according to a predefined function or again according to a random principle. Important in the case of non-periodic modulation is that the parameters determined by random principles (increment and / or time interval) are known and available within an evaluation device or an evaluation method for signal analysis. The parameters determined by a random principle (increment and / or time interval) can satisfy any predefined distribution function. You can z. B. be equal, Gaussian or poissonverteil be whereby the respective expected values of the parameters are also predefined. The advantage of non-periodic modulation is that it can suppress periodic disturbances.

Die Strahlungsquelle ist vorzugsweise eine Heizlampe und der bestrahlte Gegenstand ist vorzugsweise ein Halbleitersubstrat, das einer thermischen Behandlung unterzogen wird.The radiation source is preferably a heating lamp and the irradiated article is preferably a semiconductor substrate which is subjected to a thermal treatment.

Auf Grund der bewussten, aktiven und dadurch bekannten Modulation der Strahlungsquelle mit einem charakteristischen Parameter ist es möglich, die Unterscheidung zwischen der vom Gegenstand selbst abgestrahlten Strahlung, die für die Ermittlung der Eigenschaften des Gegenstands erforderlich ist, noch genauer von der vom Gegenstand reflektierten Strahlung der Strahlungsquelle zu unterscheiden. Auf diese Weise ist es möglich, die Eigenschaften des Gegenstands, beispielsweise die Temperatur, die Emissivität, die Transmissivität, die Reflektivität oder die Schichtdicken oder - eigenschaften eines vom Material des Gegenstands unterschiedlichen Materials auf dem Gegenstand noch genauer und in Realzeit zu bestimmen.Due to the deliberate, active and thus known modulation of the radiation source with a characteristic parameter, it is possible to make the distinction between the radiation emitted by the object itself, which is required for determining the properties of the object, even more precisely from the radiation reflected by the object To distinguish radiation source. In this way it is possible to more accurately and in real time determine the properties of the article, for example the temperature, the emissivity, the transmissivity, the reflectivity or the layer thicknesses or properties of a material different from the material of the article on the article.

Gemäß einer besonders vorteilhaften Ausführungsform der Erfindung wird die aktive Modulation der von der Strahlungsquelle abgegebenen Strahlung zu deren Charakterisierung bei der Korrektur der vom zweiten Strahlungsdetektor ermittelten Strahlung herangezogen. Durch die aktive und damit bekannte Modulation der von der Strahlungsquelle abgegebenen Strahlung ist die Charakterisierung und damit Unterscheidung dieser Strahlung von der eigentlich zu messenden Strahlung, die vom Gegenstand abgegeben wird, besonders einfach, zuverlässig und quantitativ genau.According to a particularly advantageous embodiment of the invention, the active modulation of the radiation emitted by the radiation source is used for its characterization in the correction of the radiation detected by the second radiation detector. Due to the active and thus known modulation of the radiation emitted by the radiation source, the characterization and thus differentiation of this radiation from the actual radiation to be measured, which is emitted by the object, is particularly simple, reliable and quantitatively accurate.

Die von der Strahlungsquelle abgegebene Strahlung ist vorzugsweise amplituden-, frequenz- und/oder phasen-moduliert. Je nach den vorhandenen Ge gebenheiten und Erfordernissen ist die Wahl der Modulationsart wählbar, wobei die Modulationsart insbesondere auch im Hinblick auf die Einfachheit und Zuverlässigkeit des Modulationsverfahrens, aber auch des Auswertever fahrens und des Detektionsverfahrens auswählbar ist. Dabei ist unter Amplitudenmodulation die Modulation der Modulationsamplitude zu verstehen. Bevorzugt wird jedoch mit Intensitätsmodulation gearbeitet, deren Amplitude nicht moduliert wird, sondern eventuell langsam variiert.The radiation emitted by the radiation source is preferably amplitude, frequency and / or phase modulated. Depending on the available Ge conditions and requirements, the choice of the type of modulation is selectable, the modulation type in particular with regard to the simplicity and reliability of the modulation method, but also the evaluation process and the detection method is selectable. Amplitude modulation is to be understood as the modulation of the modulation amplitude. Preferably, however, working with intensity modulation whose amplitude is not modulated, but may vary slowly.

Neben der Modultionsart ist es auch möglich, jede Signalform der Modulation einzusetzen. Besonders vorteilhaft ist es jedoch, dass bei einer Amplitudenmodulation eine Signalform mit möglichst stetigem Signalverlauf verwendet wird. Dies hat den Vorteil, dass auch bei einer Fourrier-Transformation hohe Frequenzen im wesentlichen nicht auftreten und daher auch die Zahl der Abtastungen pro Zeiteinheit bei der Detektion bzw. Verarbeitung des detektierten Signals gering bleiben kann, so dass mit einem einfachen Auswerteverfahren dennoch eine gute und genaue Messung durchführbar ist.In addition to the Modultionsart it is also possible to use each waveform of the modulation. However, it is particularly advantageous that in the case of an amplitude modulation, a signal waveform with the signal curve that is as steady as possible is used. This has the advantage that even with a Fourier transformation high frequencies essentially do not occur and therefore the number of samples per unit of time in the detection or processing of the detected signal can remain low, so that a good evaluation method nevertheless provides a good and accurate measurement is feasible.

Eine weitere vorteilhafte Ausführungsform der Erfindung besteht darin, daß die Strahlungsquelle aus mehreren Einzel-Strahlungsquellen, beispielsweise aus mehreren Lampen besteht, die zu einer oder mehreren Lampenbänken zusammenfaßbar sind. Gemäß vorteilhaften Ausführungsformen im Zusammenhang mit aus mehreren Lampen bestehenden Strahlungsquellen ist wenigstens eine der Lampen in ihrer Strahlung moduliert. An sich kann die Modulation der Strahlung einer Lampe zur Erzielung der Vorteile des erfindungsgemäßen Verfahrens ausreichen, obgleich die Modulation von nur einer Lampe nur unter Einschränkungen an die Universalität des Meßverfahrens überhaupt ein sinnvolles Ergebnis liefert. Eine besonders einfache Ansteuerung der Lampen mit einem einzigen Leistungsschalter ist insbesondere auch dann gegeben, wenn wenigstens zwei Lampen oder alle Lampen hinsichtlich ihrer Strahlung in der gleichen Weise moduliert werden. Vorteilhaft ist die Modulation der Strahlung von nur einer oder einigen Lampen, um unerwünschte Reflexionen zu vermeiden.A further advantageous embodiment of the invention is that the radiation source consists of a plurality of individual radiation sources, for example of a plurality of lamps, which can be combined to form one or more lamp banks. According to advantageous embodiments in connection with radiation sources consisting of a plurality of lamps, at least one of the lamps is modulated in their radiation. In itself, the modulation of the radiation of a lamp to achieve the advantages of the method according to the invention may be sufficient, although the modulation of only one lamp only makes a meaningful result under restrictions to the universality of the measuring method. A particularly simple control of the lamps with a single circuit breaker is given in particular even if at least two lamps or all lamps are modulated in terms of their radiation in the same manner. Advantageously, the modulation of the radiation of only one or a few lamps to avoid unwanted reflections.

Je nach den Anwendungsfällen und Gegebenheiten ist es jedoch auch vorteilhaft, die Strahlung der Lampen unterschiedlich zu modulieren, beispielsweise dann, wenn die Lampenstrahlung in Abhängigkeit von der Lage der Lampen oder von der jeweils spezifischen Lampe gegenüber der Strahlung anderer Lampen oder gegenüber anderen Lampen unterschieden werden soll.Depending on the applications and circumstances, however, it is also advantageous to modulate the radiation of the lamps differently, for example, when the lamp radiation depending on the position of the lamps or the respective specific lamp with respect to the radiation of other lamps or other lamps are distinguished should.

Die Strahlenmodulation der einzelnen Lampen oder Strahlungsquellen ist vorzugsweise für wenigstens einige von ihnen zeitlich synchron oder in einer festen zeitlichen Zuordnung zueinander vorgesehen, obgleich in bestimmten Anwendungsfällen auch zeitlich nicht synchrone Strahlenmodulationen vorteilhaft sein können.The radiation modulation of the individual lamps or radiation sources is preferably for at least some of they are temporally synchronous or provided in a fixed temporal relationship to each other, although temporally non-synchronous beam modulations may be advantageous in certain applications.

Gemäß einer besonders vorteilhaften Ausgestaltung der Erfindung ist der Modulationsgrad und insbesondere die Modulationstiefe der von der Strahlungsquelle abgegebenen Strahlung, - gegebenenfalls auch von Strahlungsquelle zu Strahlungsquelle unterschiedlich -, von der abgestrahlten Lampenintensität unabhängig. Diese sogenannte Absolut-Modulation ist also unabhängig vom Grundpegel oder Gleichstromsignal, mit dem die Strahlungsquelle oder Lampe angesteuert wird. Diese Ausführungsform der Erfindung weist den Vorteil auf, daß während des Anstiegs der Intensität der Strahlenquelle, der gegebenenfalls schnell vorgenommen werden soll, die volle Ansteuerung ausgenutzt werden kann und nicht durch eine zu große Modulation in ihrer Intensität eingeschränkt ist.According to a particularly advantageous embodiment of the invention, the degree of modulation and in particular the modulation depth of the radiation emitted by the radiation source, - possibly also different from radiation source to radiation source - independent of the radiated lamp intensity. This so-called absolute modulation is thus independent of the base level or DC signal with which the radiation source or lamp is driven. This embodiment of the invention has the advantage that during the increase in the intensity of the radiation source, which should optionally be made quickly, the full drive can be exploited and is not limited by an excessive modulation in their intensity.

In anders gelagerten Anwendungsfällen ist jedoch die Ausführungsform der Erfindung vorteilhafter, bei der der Modulationsgrad bzw. die Modulationstiefe von der abgestrahlten Intensität der Strahlungsquelle abhängig ist. Diese sogenannte Relativ-Modulation, bei der beispielsweise die Stärke des Wechselstrom-Ansteuersignals von der Stärke des Gleichstrom-Ansteuersignals der Strahlungsquelle abhängt oder ihr proportional ist, hat den Vorteil, daß der relative Modulationgrad konstant ist oder sich nur in geringerem Maße ändert, wodurch die Detektion der Modulation und die Auswertung einfacher und mit weniger aufwendigen Geräten durchführbar ist.In other applications, however, the embodiment of the invention is more advantageous, in which the degree of modulation or the depth of modulation depends on the radiated intensity of the radiation source. This so-called relative modulation, in which, for example, the magnitude of the AC drive signal depends on or is proportional to the intensity of the DC drive signal of the radiation source, has the advantage that the relative modulation degree is constant or changes only to a lesser extent, whereby the Detection of the modulation and evaluation is easier and less expensive devices feasible.

Bei einer weiteren Ausführungsform der Erfindung wird der Modulationsgrad oder die Modulationstiefe gesteuert oder auch aktiv geregelt.In a further embodiment of the invention, the degree of modulation or the depth of modulation is controlled or actively regulated.

Gemäß einer weiteren sehr vorteilhaften Ausgestaltung der Erfindung ist Lampenintensität und/oder die Modulation selbst pulsweiten-moduliert. Gemäß einer alternativen oder zusätzlichen Ausführungsform der Erfindung wird die Strahlung der Strahlungsquelle durch Verwendung von Tabellenwerten mit einem Datenverarbeitungsprogramm moduliert. Eine weitere sehr vorteilhafte Ausgestaltung der Erfindung besteht auch darin, die Strahlung durch Ändern der Zählerfrequenz von Generatoren für die Pulsweiten-Modulation zu modulieren.According to a further very advantageous embodiment of the invention, the lamp intensity and / or the modulation itself is pulse-width-modulated. According to an alternative or additional embodiment of the invention, the radiation of the radiation source is modulated by using table values with a data processing program. Another very advantageous embodiment of the invention is also to modulate the radiation by changing the counter frequency of generators for the pulse width modulation.

Die Lampenleistung wird durch Pulsweiten-Modulation verändert. Die Strahlungsintensität ist dabei eine Funktion der Wendeltemperatur, die jedoch im stationären, eingeschwungenen Zustand direkt mit der Lampenleistungen korrespondiert.The lamp power is changed by pulse width modulation. The radiation intensity is a function of the spiral temperature, which however corresponds directly to the lamp power in the stationary, steady state.

Die Strahlung der Strahlungsquelle wird vorzugsweise durch eine Modulation des Ansteuersignals bzw. der Ansteuersignale für die Strahlungsquelle bzw. die Lampen moduliert. Wie im weiteren im einzelnen noch ausgeführt werden wird, ist die Stelle, an der das Ansteuersignal innerhalb der Signalerzeugung moduliert wird, je nach den Erfordernissen und Gegebenheiten wählbar. Besonders vorteilhaft ist es dabei, wenn das Ansteuersignal nach dessen Erzeugung unmittelbar vor Zuführung zu der Strahlungsquelle oder den Lampen moduliert wird.The radiation of the radiation source is preferably modulated by a modulation of the drive signal or the drive signals for the radiation source or the lamps. As will be explained in more detail below, the point at which the drive signal is modulated within the signal generation, depending on the needs and circumstances selectable. It is particularly advantageous if the drive signal is modulated immediately after its generation before being fed to the radiation source or the lamps.

Die vorliegende Erfindung ist mit großem Vorteil zur Bestimmung der Temperatur, Reflektivität und/oder Emissivität eines Gegenstands anwendbar, beispielsweise im Zusammenhang mit einer Vorrichtung zur thermischen Behandlung von Substraten etwa in einem Ofen, in dem die Substrate schnell und mit einem möglichst genauen, vorgegebenen Temperaturverlauf aufgeheizt und abgekühlt werden.The present invention is of great advantage for determining the temperature, reflectivity and / or emissivity of an article applicable, for example in connection with a device for the thermal treatment of substrates such as in an oven, in which the substrates are fast and with the most accurate, predetermined temperature profile be heated and cooled.

Gemäß der Erfindung wird also die von wenigstens einer Strahlungsquelle, beispielsweise eine Heizlampe abgegebene Strahlung und die vom aufzuheizenden Gegenstand herrührende Strahlung ermittelt, wobei sich letztere aus der von dem Gegenstand emittierten Strahlung und der am Gegenstand reflektierten Strahlung zusammensetzt. Durch die beiden Messungen ist es möglich, die vom Gegenstand reflektierte Strahlung der Strahlungsquellen heraus zu korrigieren und damit die emittierte Strahlung, also die Wärmestrahlung des Gegenstands zu bestimmen, der normalerweise und auch im Falle eines Wafers kein schwarzer Strahler ist. Bei Kenntnis der Emissivität dieses Gegenstandes kann nunmehr auf die Strahlung eines schwarzen Körpers zurückgerechnet werden.According to the invention, therefore, the radiation emitted by at least one radiation source, for example a heating lamp, and the radiation originating from the object to be heated are determined, the latter being composed of the radiation emitted by the object and the radiation reflected by the object. By means of the two measurements, it is possible to correct the radiation of the radiation sources reflected by the object and thus to determine the emitted radiation, ie the thermal radiation of the object, which normally and also in the case of a wafer is not a blackbody. With knowledge of the emissivity of this object can now be calculated back to the radiation of a black body.

Gemäß der vorliegenden Erfindung werden die Amplituden der modulierten Komponenten, die auch als Wechselstrom- bzw. Wechselspannungs(AC)-Komponenten bezeichnet werden, ins Verhältnis gesetzt, die vom für den Gegenstand vorgesehenen Strahlungsdetektor und vom für die Strahlungsquellen vorgesehenen Strahlungsdetektor gemessen werden. Die sich aus dem Amplitudenverhältnis ergebende Zahl ist in erster Näherung proportional zur Reflektivität des Gegenstandes, beispielsweise des Wafers. Diese Zahl wird nun zweimal für die weitere Auswertung benutzt. Erstens wird sie benutzt, um die von dem Gegenstand emittierte Strahlung, also die Wärmestrahlung des Gegenstandes von der am Gegenstand reflektierten Strahlung der Strahlungsquelle zu unterscheiden. Zweitens wird diese Zahl benutzt, um die vom Gegenstand emittierte Strahlung, also die Wärmestrahlung auf die Strahlung eines schwarzen Körpers der gleichen Temperatur zurück zu skalieren. Durch Einsetzen des dabei gewonnenen, zurückskallierten Temperaturwert in die invertierte Planck'sche Strahlungsformel ergibt sich dann eindeutig eine Temperatur. Da das genannte Amplitudenverhältnis der Modulationen bei der Auswertung also zweimal verwendet wird, muß dieses möglichst genau gemessen werden, um bei der Auswertung und der Ermittlung der Temperatur des Gegenstandes genaue Werte zu erhalten. Das erfindungsgemäße Verfahren ermöglicht eine wesentlich genauere Bestimmung dieses Amplitudenverhältnisses, da die Modulationsparameter für jeden Heizzustand optimal vorgebbar sind und sowohl die Modulation als auch deren Auswertung wesentlich vereinfacht wird.In accordance with the present invention, the amplitudes of the modulated components, also referred to as AC (AC) components, are proportioned as measured by the radiation detector provided for the article and the radiation detector provided for the radiation sources. The resulting from the amplitude ratio number is proportional to the reflectivity of the object, for example, the wafer in a first approximation. This number will now be used twice for further evaluation. First, it is used to distinguish the radiation emitted by the object, ie the heat radiation of the object from the radiation of the radiation source reflected by the object. Secondly, this number is used to scale back the radiation emitted by the object, ie the thermal radiation, back to the radiation of a black body of the same temperature. By inserting the thus obtained, zurückskallierten temperature value in the inverted Planck's radiation formula then clearly results in a temperature. Since the said amplitude ratio of the modulations is thus used twice in the evaluation, this must be possible be accurately measured to obtain accurate values in the evaluation and the determination of the temperature of the object. The inventive method allows a much more accurate determination of this amplitude ratio, since the modulation parameters for each heating state are optimally predetermined and both the modulation and its evaluation is much easier.

Bei einer besonders bevorzugten Ausführungsform der Erfindung ist der erste Detektor ein Strahlungsdetektor, der auf einfache und zuverlässige Weise die von der Strahlungsquelle abgegebene Strahlung mißt. Dabei wird die von der Strahlungsquelle abgegebene Strahlung vorteilhafterweise über optische Leitungen oder Lichtkanäle zu dem Strahlungsdetektor geleitet. Um eine akkurate Messung zu gewährleisten, sind die Strahlungsquellen und die optischen Leitungen oder Lichtkanäle relativ zueinander derart angeordnet, daß der erste Strahlungsdetektor ein Signal erzeugt, das frei von Einflüssen von Filamenthaltevorrichtungen oder anderen, den Strahlungsfluß oder die Strahlungstemperatur der Strahlungsquelle beeinträchtigender Mittel ist.In a particularly preferred embodiment of the invention, the first detector is a radiation detector which measures in a simple and reliable manner the radiation emitted by the radiation source. In this case, the radiation emitted by the radiation source is advantageously conducted via optical lines or light channels to the radiation detector. In order to ensure an accurate measurement, the radiation sources and the optical conduits or light channels are arranged relative to one another such that the first radiation detector generates a signal which is free of influences from filament holders or other means interfering with the radiation flux or radiation temperature of the radiation source.

Gemäß einer anderen Ausführungsform der Erfindung kann der erste Detektor ein Temperatursensor, wie z. B. ein Thermoelement, sein, mit dem die Lampentemperatur und somit die abgestrahlte Intensität ermittelbar ist.According to another embodiment of the invention, the first detector, a temperature sensor, such. Example, a thermocouple, with which the lamp temperature and thus the radiated intensity can be determined.

Bei einer weiteren Ausführungsform der Erfindung mißt der erste Detektor einen beliebigen mit der von der Strahlungsquelle abgegebenen Strahlung in Beziehung stehenden Parameter. So kann z. B. die Intensität über ein Impedanz-Meßvorrichtung, die die Impedanz (z. B. den Ohmschen Widerstand) eines Lampenfilaments mißt, ermittelt werden. Über eine geeignete Verarbeitungseinheit kann bei Kenntnis der Impedanz-Intensitäts-Relation der Strahlungsquelle, wie z. B. einer Heizlampe, deren abgestrahlte Intensität bzw. ein hierzu proportionaler Parameter ermittelt werden.In a further embodiment of the invention, the first detector measures any parameter related to the radiation emitted by the radiation source. So z. For example, the intensity may be determined via an impedance measuring device that measures the impedance (eg, the ohmic resistance) of a lamp filament. With a suitable processing unit, knowing the impedance-intensity relation of the radiation source, such as B. a heating lamp whose radiated intensity or a proportional thereto parameters are determined.

Die Erfindung wird nachstehend im Zusammenhang mit dem Beispiel einer Vorrichtung zum Aufheizen von Halbleiterwafern unter Bezugnahme auf die Figuren erläutert. Es zeigen:

Fig. 1
einen Längsschnitt durch eine Schnellheizanlage zur Behandlung von Halbleiterwafern in schematischer Darstellung,
Fig. 2
einen Querschnitt entlang der in Fig. 1 eingezeichneten Schnittlinie II-II,
Fig. 3a
und 3b schematische Diagramme zur Erläuterung des Modulationsgrads bzw. der Modulationstiefe unabhängig oder in Abhängigkeit von der Basisintensität der Strahlungsquelle und
Fig. 4
eine schematische Darstellung eines Blockschaltbilds zur Ansteuerung einer Strahlungsquelle bzw. einer Lampe nach dem erfindungsgemäßen Verfahren.
The invention will be explained below in connection with the example of a device for heating semiconductor wafers with reference to the figures. Show it:
Fig. 1
a longitudinal section through a rapid heating system for the treatment of semiconductor wafers in a schematic representation,
Fig. 2
a cross section along the drawn in Figure 1 section line II-II,
Fig. 3a
and FIG. 3b are schematic diagrams for explaining the degree of modulation or the depth of modulation independently or as a function of the basic intensity of the radiation source and
Fig. 4
a schematic representation of a block diagram for controlling a radiation source or a lamp according to the inventive method.

Die in Fig. 1 und 2 dargestellte Ausführungsform eines Schnellheizofens zur Behandlung von Halbleiterwafern 2 zeigt eine vorzugsweise aus Quarzglas bestehende Reaktionskammer 1 mit einem darin befindlichen Halbleiterwafer 2. Die Reakionskammer 1 ist von einem Gehäuse 3 umgeben, das jeweils oben und unten Lampen 4, 5 aufweist, deren Strahlung auf die Reaktionskammer 1 gerichtet sind.1 and 2 shows a preferably quartz glass reaction chamber 1 with a semiconductor wafer 2 located therein. The reaction chamber 1 is surrounded by a housing 3, which has lamps 4, 5 at the top and bottom, respectively has, whose radiation is directed to the reaction chamber 1.

Vorteilhafterweise besteht die Reaktionskammer 1 im wesentlichen aus einem für die Lampenstrahlung im wesentlichen transparenten Material, das auch hinsichtlich der Meßwellenlängen oder der Meßwellenlängenspektren der Pyrometer oder der verwendeten Strahlungsdetektoren transparent ist. Mit Quarzgläser und/oder Saphir, die einen über das Lampenspektrum gemittelten Absorptionskoeffizienten von etwa 0.1 1/cm bis 0.001 1/cm haben, lassen sich geeignete Reaktionskammern für Schnellheizsysteme aufbauen, bei denen die Dicke der Reaktionskammerwand zwischen 1mm und mehreren Zentimetern, beispielsweise 5 cm betragen kann. Je nach Reaktionskammerwanddicke kann die Materialauswahl hinsichtlich des Absorptionskoeffizienten erfolgen.Advantageously, the reaction chamber 1 consists essentially of a substantially transparent to the lamp radiation material, which is also transparent with respect to the measuring wavelengths or the Meßwellenlängenspektren the pyrometer or the radiation detectors used. With quartz glasses and / or sapphire, which has an averaged absorption coefficient over the lamp spectrum from about 0.1 1 / cm to 0.001 1 / cm, suitable reaction chambers for rapid heating systems can be constructed in which the thickness of the reaction chamber wall can be between 1 mm and several centimeters, for example 5 cm. Depending on the reaction chamber wall thickness, the choice of material can be made with regard to the absorption coefficient.

Kammerwanddicken im Zentimeterbereich sind insbesondere dann erforderlich, wenn in der Reaktionskammer 1 ein Unterdruck (bis hin zum Ultra-Hochvakuum) oder ein Überdruck erzeugt werden soll. Beträgt beispielsweise der Reaktionskammerdurchmesser etwa 300mm, so erhält man mit einer Quarzglasdicke von ca. 12mm bis 20mm eine hinreichende mechanische Stabilität der Kammer 1, so daß diese evakuiert werden kann. Die Reaktionskammerwanddicke wird entsprechend dem Wandmaterial, der Kammergröße und der Druckbelastungen dimensioniert.Chamber thicknesses in the centimeter range are particularly necessary if in the reaction chamber 1, a negative pressure (up to the ultra-high vacuum) or an overpressure to be generated. If, for example, the reaction chamber diameter is about 300 mm, a sufficient mechanical stability of the chamber 1 is obtained with a quartz glass thickness of about 12 mm to 20 mm, so that it can be evacuated. The reaction chamber wall thickness is dimensioned according to the wall material, the chamber size and the pressure loads.

Ein schematisch dargestelltes Pyrometer 6 (vgl. insbesondere Fig. 2) mit einem großen Eintrittswinkel mißt die vom Halbleiterwafer 2 emittierte Strahlung sowie die am Halbleiterwafer 2 reflektierte Strahlung der Lampen 5, die im dargestellten Ausführungsbeispiel als Stablampen ausgebildet sind. Eine Anordnung dieser Art ist bekannt und beispielsweise in der DE 44 37 361 C oder der nicht vorveröffentlichten DE 197 37 802 A derselben Anmelderin beschrieben, so daß zur Vermeidung von Wiederholungen darauf Bezug genommen wird, und diese Druckschriften insofern zum Inhalt der vorliegenden Beschreibung gemacht werden.A schematically represented pyrometer 6 (cf., in particular, FIG. 2) with a large entrance angle measures the radiation emitted by the semiconductor wafer 2 and the radiation of the lamps 5 reflected at the semiconductor wafer 2, which lamps are designed as flashlights in the illustrated embodiment. An arrangement of this type is known and described for example in DE 44 37 361 C or the non-prepublished DE 197 37 802 A the same applicant, so that reference is made to avoid repetition, and these documents are made insofar as the content of the present description ,

Als Stablampen werden bevorzugt Halogenlampen verwendet, deren Filament wenigstens teilweise eine Wendelstruktur aufweisen. Durch eine wenigstens teilweise Wendelstruktur läßt sich vorteilhaft ein bestimmtes vordefiniertes geometrisches und spektrales Abstrahlprofil der Lampe erreichen. Hierbei kann das Filament der Lampe z. B. abwechselnd gewendelte und ungewendelte Filamentabschnitte umfassen. Das Abstrahlprofil (sowohl das geometrische als auch das spektrale) ist in diesem Falle im wesentlichen durch den Abstand benachbarter gewendelter Filamentabschnitte bestimmt. Eine weitere Möglichkeit das Lampenabstrahlprofil zu definieren besteht z. B. darin, daß die Dichte der Filamentstruktur (z. B. der Wendeldichte) entlang des Filaments variiert wird.As flashlights halogen lamps are preferably used, the filament at least partially have a helical structure. By means of an at least partially helical structure, it is advantageously possible to achieve a specific predefined geometric and spectral emission profile of the lamp. Here, the filament of the lamp z. B. alternately coiled and uncoiled filament sections. The radiation profile (both the geometric and the spectral) is determined in this case essentially by the distance between adjacent coiled filament sections. Another way to define the Lampenabstrahlprofil consists z. In that the density of the filament structure (eg, the filament density) is varied along the filament.

Soll das Lampenprofil steuerbar sein, so lassen sich vorteilhaft Lampen, vorzugsweise Stablampen, mit mehreren einzelansteuerbaren Filamenten einsetzen. Lampen mit steuerbarem Lampenprofil sind insbesondere in Schnellheizanlagen zur Wärmebehandlung großflächiger Substrate, wie z. B. 300mm-Halbleiterwafer, vorteilhaft, da sich mit diesen Lampen und einer geeigneten Lampenansteuervorrichtung ein sehr homogenes Temperaturprofil entlang der Substratoberfläche erzielen läßt. Durch die Superposition der Einzelabstrahlprofile der Filamente ergibt sich ein in weiten Bereichen einstellbares Gesamtabstrahlprofil der Lampe. Im einfachsten Falle umfaßt z. B. eine Halogenlampe zwei Filamente, z. B. jeweils mit Wendelstruktur oder wenigstens teilweise gewendelter Struktur, wobei die Wendeldichte und/oder der Abstand der gewendelten Filamentabschnitte des ersten Filaments vom ersten Ende zum zweiten Ende der Lampe zunimmt, und die Wendeldichte und/oder der Abstand der gewendelten Filamentabschnitte des zweiten Filaments entsprechend umgekehrt vom ersten zum zweiten Ende der Lampe abnimmt. Das Gesamtabstrahlprofil kann somit durch die Wahl der Stromstärke in den beiden Filamenten in weiten Bereichen variiert werden. Eine weitere Ausgestaltungsmöglichkeit einer Lampe mit steuerbarem Abstrahlprofil besteht darin, daß das Filament der Lampe wenigstens drei elektrische Anschlüsse umfaßt, wobei jeweils zwischen den Anschlüssen unterschiedliche Betriebsspannungen gelegt werden. Dadurch läßt sich abschnittsweise die Filamenttemperatur, und damit die Abstrahlcharakteristik der Lampe, entlang des Filaments steuern.If the lamp profile is to be controllable, it is advantageous to use lamps, preferably flashlights, with a plurality of individually controllable filaments. Lamps with controllable lamp profile are particularly in fast heating systems for heat treatment of large-area substrates such. As 300mm semiconductor wafer, advantageous because can be achieved along the substrate surface with these lamps and a suitable Lampenansteuervorrichtung a very homogeneous temperature profile. The superposition of the individual emission profiles of the filaments results in an overall radiation profile of the lamp which can be set in a wide range. In the simplest case, z. As a halogen lamp two filaments, z. B. each with helical structure or at least partially coiled structure, wherein the coil density and / or the distance of the coiled filament portions of the first filament from the first end to the second end of the lamp increases, and the coil density and / or the distance of the coiled filament sections of the second filament accordingly reversed from the first to the second end of the lamp decreases. The Gesamtabstrahlprofil can thus be varied by the choice of the current in the two filaments in wide ranges. A further embodiment possibility of a lamp with controllable emission profile is that the filament of the lamp comprises at least three electrical connections, wherein in each case different operating voltages are applied between the terminals. This can be done sections, the filament temperature, and thus control the radiation characteristics of the lamp, along the filament.

Alternativ zu den bisher beschriebenen Lampen lassen sich auch Plasma- oder Bogenlampen einsetzen, wobei auch hier das Abstrahlprofil einstellbar ist. So läßt sich beispielsweise das Lampenspektrum über die Stromdichte vom UV-Bereich bis hin zum nahen Infrarot einstellen. Die Bogenlampen haben hinsichtlich der aktiven Modulation den Vorteil, daß sie mit höherer Modulationsfrequenz betrieben werden können. Dadurch vereinfachen sich sowohl die Signalverarbeitungselektronik als auch die Auswerteverfahren.As an alternative to the lamps described so far, it is also possible to use plasma or arc lamps, the emission profile also being adjustable here. For example, the lamp spectrum can be adjusted via the current density from the UV range to the near infrared. The arc lamps have the advantage in terms of active modulation that they can be operated at a higher modulation frequency. This simplifies both the signal processing electronics and the evaluation.

Ein weiteres Pyrometer 7 erhält über optische Leitungen oder Lichtkanäle 8 das von den Lampen 5 abgestrahlte Licht direkt zugeleitet. Dabei sind die Strahlungsquellen und/oder die Lichtkanäle bevorzugt so angeordnet, daß das Lampenpyrometersignal von einem Lampen- oder Filamentabschnitt resultiert, der frei von Filamenthaltevorrichtungen oder anderen, den Strahlungsfluß oder die Temperatur des durch die Lichtkanäle beobachteten Filament- oder Lampenabschnitts beeinträchtigenden Mitteln ist. Um Wiederholungen hinsichtlich des Lampenpyrometers 7 und der Anordnung zum Bestrahlen des Lampenpyrometers 7 mit dem Licht der Lampen 5 zu vermeiden, wird auf die das gleiche Anmeldedatum aufweisende DE 197 54 385 derselben Anmelderin verwiesen, die insofern zum Inhalt der vorliegenden Anmeldung gemacht wird.Another pyrometer 7 receives via optical lines or light channels 8, the light emitted by the lamps 5 directly supplied. In this case, the radiation sources and / or the light channels are preferably arranged such that the lamp pyrometer signal results from a lamp or filament section which is free of filament holding devices or other means interfering with the radiation flux or the temperature of the filament or lamp section observed through the light channels. In order to avoid repetition with respect to the lamp pyrometer 7 and the arrangement for irradiating the lamp pyrometer 7 with the light of the lamps 5, reference is made to the same applicant's DE 197 54 385, which is incorporated herein by reference.

Die Ausgangssignale der Pyrometer 6 und 7 werden einer nicht dargestellten Auswerteschaltung zugeführt, die die vom Halbleiterwafer 2 emittierte Strahlung dadurch ermittelt, daß sie die auf das Pyrometer 6 fallende Strahlung mit der vom Pyrometer 7 ermittelten Strahlung in Bezug setzt und dadurch die Strahlung ermittelt, die vom Halbleiterwafer 2 emittiert wird. Dies ist deshalb möglich, weil die von den Lampen 5 emittierte Strahlung aktiv und in einer definierten Weise moduliert ist. Diese Modulation ist auch in der vom Wafer-Pyrometer 6 aufgenommenen Strahlung enthalten, so daß durch Vergleich oder in Beziehungsetzen der Modulationsgrade oder Modulationstiefen der von den Pyrometern 6 und 7 aufgenommenen Strahlung eine Kompensation der vom Halbleiterwafer 2 reflektierten Lampenstrahlung in der vom Waferpyrometer 6 aufgefangenen Strahlung möglich ist, und dadurch die vom Halbleiterwafer 2 emittierte Strahlung und damit dessen Temperatur, Reflektivität, Transmissivität und/oder Emissivität genau gemessen werden kann.The output signals of the pyrometer 6 and 7 are supplied to an evaluation circuit, not shown, which detects the radiation emitted by the semiconductor wafer 2 by the fact that it sets the radiation falling on the pyrometer 6 with the radiation detected by the pyrometer 7 in relation and thereby determines the radiation from Semiconductor wafer 2 is emitted. This is possible because the radiation emitted by the lamps 5 is actively and modulated in a defined manner. This modulation is also contained in the radiation received by the wafer pyrometer 6, so that by comparison or in relationship sets of modulation depths or modulation depths of the radiation received by the pyrometers 6 and 7 compensation of reflected from the semiconductor wafer 2 lamp radiation in the field captured by the wafer pyrometer 6 radiation is possible, and thereby the radiation emitted by the semiconductor wafer 2 and thus its temperature, reflectivity, transmissivity and / or emissivity can be measured accurately.

Ein weiteres, entsprechendes Lampenpyrometer, wie dies in Fig. 1 und 2 dargestellt und zuvor beschrieben ist, kann gemäß einer weiteren Ausführungsform auch mit entsprechenden Lichtleitungen oder -schächten auf der anderen Seite des Gehäuses 3 zur Messung der Lampenstrahlung der oberen Lampen 4 vorgesehen sein. Das obere Lampenpyrometer entspricht dabei in seiner Funktion dem des unteren Lampenpyrometers 7, indem das obere Lampenpyrometer die Strahlung und deren Intensität bezüglich der oberen Lampen 4 mißt. Dabei ist es besonders vorteilhaft, wenn die Modulationsart oder der Modulationsgrad der Lampen der oberen Lampenbank unterschiedlich zum Modulationsgrad oder der Modulationsart der unteren Lampenbank ist. Durch Vergleich des vom Waferpyrometer 6 aufgenommenen Lichtes bzw. seiner Modulationsart oder seines Modulationsgrads mit der Modulationsart bzw. dem Modulationsgrad der mit dem oberen Lampen-Pyrometer ermittelten Intensität in einer nicht dargestellten Auswerteeinheit ist es darüber hinaus möglich, auch die Transmissivität des Halbleiterwafers 2 zu ermitteln und daraus Rückschlüsse auf die Temperatur, die Emissivität und/oder die Reflektivität des Wafers 2 zu ziehen.A further, corresponding lamp pyrometer, as shown in FIGS. 1 and 2 and described above, according to a further embodiment may also be provided with corresponding light pipes or shafts on the other side of the housing 3 for measuring the lamp radiation of the upper lamps 4. The upper lamp pyrometer corresponds in its function to that of the lower lamp pyrometer 7 in that the upper lamp pyrometer measures the radiation and its intensity with respect to the upper lamps 4. It is particularly advantageous if the type of modulation or the degree of modulation of the lamps of the upper bank of lamps is different from the degree of modulation or the modulation of the lower bank of lamps. By comparing the light received by the wafer pyrometer 6 or its modulation type or its degree of modulation with the modulation or the degree of modulation of the intensity determined by the upper lamp pyrometer in an evaluation unit, not shown, it is also possible to determine the transmissivity of the semiconductor wafer 2 and to draw conclusions about the temperature, the emissivity and / or the reflectivity of the wafer 2.

In den in Fig. 3a und 3b dargestellten Beispielen für eine periodische Modulation sind jeweils die Intensitäten I der Strahlungsquellen über der Zeit aufgetragen. Wie Fig. 3a zeigt, ist der Modulationsgrad bzw. die Modulationstiefe im wesentlichen konstant und unabhängig von der von der Strahlungsquelle abgegebenen Strahlungsintensität, während bei dem in Fig. 3b dargestellten Beispiel der Modulationsgrad oder die Modulationstiefe von der abgestrahlten Intensität der Strahlungsquelle bzw. der Größe ihres Ansteuersignals abhängt bzw. zu ihr proportional dazu ist.In the examples of a periodic modulation illustrated in FIGS. 3a and 3b, the intensities I of the radiation sources are plotted over time. As shown in FIG. 3a, the degree of modulation or the depth of modulation is essentially constant and independent of the radiation intensity emitted by the radiation source, while in the example shown in FIG. 3b the degree of modulation or the depth of modulation depends on the radiated intensity of the radiation source or the size its drive signal depends or is proportional to her.

Die sogenannte Absolut-Modulation gemäß Fig. 3a weist den Vorteil auf, daß während des Hochheizens des Halbleiterwafers 2 bzw. der Reaktionskammer 1 die Heizleistung durch die Modulation praktisch nicht beeinträchtigt wird, und daher die gesamte Intensität für die schnelle Aufheizung zur Verfügung steht. Dagegen weist die sogenannte Relativ-Modulation gemäß Fig. 3b den Vorteil auf, den Modulationsgrad bzw. die Modulationstiefe um so stärker vorliegen zu haben, je höher die Abstrahlleistung der Strahlungsquellen ist. Ein Steuern oder aktives Regeln der Modulationstiefe ist ebenfalls möglich.The so-called absolute modulation according to FIG. 3a has the advantage that, during the high heating of the semiconductor wafer 2 or the reaction chamber 1, the heating power is practically unaffected by the modulation, and therefore the entire intensity for the rapid heating is available. In contrast, the so-called relative modulation according to FIG. 3b has the advantage of having the degree of modulation or the depth of modulation all the more, the higher the radiation power of the radiation sources. Controlling or actively controlling the modulation depth is also possible.

In Fig. 4 ist eine schematische Schaltungsanordnung zur Ansteuerung einer Strahlungsquelle oder Lampen 11 zur Erzeugung einer Strahlung bzw. eines Strahlungsverlaufs für eine bestimmte Wafertemperatur bzw. eines bestimmten Temperaturverlaufs dargestellt, mit der der Wafer 2 aufgeheizt bzw. durch entsprechendes Abschalten oder Verringern der Intensität der Lampen abgekühlt werden soll.In Fig. 4 is a schematic circuit arrangement for controlling a radiation source or lamps 11 for generating a radiation or a radiation profile for a certain wafer temperature or a specific temperature profile is shown, heated by the wafer 2 or by appropriately switching off or reducing the intensity of the Lamps should be cooled.

In einem Komparator 11 wird die mit dem Waferpyrometer 6 indirekt gemessene Wafertemperatur (Anschluß 13) jeweils mit einer Soll-Temperatur 14 verglichen und das Vergleichssignal einem Regler 15 zugeführt, an dessen Ausgang das Ansteuersignal entsprechend der Einstellelemente 16, 17 auf die beiden Lampen bzw. Lampenbänke aufgeteilt wird. Danach wird das Ansteuersignal durch Aufteiler 18, 19 auf die einzelnen Lampen 4, 5 der Lampenbänke aufgeteilt, wobei der Übersichtlichkeit halber lediglich jeweils ein Aufteiler 18, 19 konkret dargestellt ist, der das Ansteuersignal an die Lampe 4 bzw. 5 abgibt.In a comparator 11, the indirectly measured with the wafer pyrometer 6 wafer temperature (terminal 13) is compared with a target temperature 14 and the comparison signal fed to a controller 15, at whose output the drive signal corresponding to the adjusting elements 16, 17 on the two lamps or Divided lamp banks becomes. Thereafter, the drive signal is divided by splitter 18, 19 on the individual lamps 4, 5 of the lamp banks, wherein for the sake of clarity, only one splitter 18, 19 is shown concretely, which emits the drive signal to the lamp 4 and 5 respectively.

Besonders vorteilhaft ist es, wenn das Ansteuersignal unmittelbar vor der Lampe 4 bzw. 5 moduliert ist, da auf diese Weise Verzerrungen vermieden werden können, die durch die Lampenansteuerschaltung hervorgerufen werden könnten. In diesem Falle erfolgt die Modulation also am Schaltungspunkt 20 bzw. 21 durch nicht dargestellte Modulationseinrichtungen, beispielsweise durch programmierbare Kurven-, Amplituden- und/oder Frequensverläufe.It is particularly advantageous if the drive signal is modulated immediately in front of the lamp 4 or 5, since in this way distortions which could be caused by the lamp drive circuit can be avoided. In this case, the modulation is thus carried out at the circuit point 20 or 21 by means not shown modulation means, for example by programmable curves, amplitude and / or Frequensverläufe.

Die Modulation kann jedoch auch an anderen Stellen innerhalb der Ansteuerschaltung gemäß Fig. 4, beispielsweise am Schaltungspunkt 22 oder am Schaltungspunkt 20 vor oder nach dem Regler 23 vorgenommen werden. In diesem Falle ist jedoch eine individuelle Modulation der Ansteuersignale für jeweils eine Lampe nicht möglich, da die Modulation des gemeinsamen Ausgangssignals einheitlich erfolgt.However, the modulation can also be made at other locations within the drive circuit according to FIG. 4, for example at the circuit point 22 or at the circuit point 20 before or after the controller 23. In this case, however, an individual modulation of the drive signals for each lamp is not possible because the modulation of the common output signal is uniform.

Die Modulation ist mittels eines entsprechenden Datenverarbeitungsprogramms auf einfache Weise durchführbar. Durch Software-Tabellen lassen sich praktisch sämtliche Kurvenformen und Frequenzen frei programmieren, wobei die Länge der Tabelle die Frequenz bestimmt, da die Tabelle mit einer festen Zeitbasis (zum Beispiel 1 ms) abarbeitbar ist und nach Erreichen des Tabellenendes beliebig oft wiederholt werden kann. Die Tabelle kann zum Beispiel mit einer Basis von 28 = 256 angelegt sein, wobei der Algorithmus für die Modulation beispielsweise lautet: C mod = C D C ⋅ T ( n ) 2 Basis

Figure imgb0001
The modulation can be carried out in a simple manner by means of a corresponding data processing program. Software tables allow virtually all waveforms and frequencies to be freely programmed, with the length of the table determining the frequency since the table can be processed with a fixed time base (for example 1 ms) and can be repeated as often as desired after reaching the end of the table. For example, the table may be applied with a base of 2 8 = 256, where the algorithm for the modulation is, for example: C mod = C D C ⋅ T ( n ) 2 Base
Figure imgb0001

Dabei ist Cmod der Modulationsgrad, der CDC der Wert der nicht modulierten bzw. Grund-Intensität oder -Amplitude und T(n) sind die jeweiligen diskreten Tabellenwerte.Where C mod is the degree of modulation, C DC is the value of the unmodulated or fundamental intensity or amplitude, and T (n) are the respective discrete table values.

Auf diese Weise können beliebige Modulationsgrade oder -tiefen, Kurvenformen und Frequenzen auf einfache Weise programmiert werden.In this way, any modulation degrees or depths, waveforms and frequencies can be easily programmed.

Mit beispielsweise einer 100%igen Modulation bei 125 Hz ergeben sich die diskreten Tabellenwerte mit
256, 435, 512, 435, 256, 76, O, 76.With, for example, a 100% modulation at 125 Hz, the discrete table values result
256, 435, 512, 435, 256, 76, O, 76.

Der Durchschnittswert der Tabellenwerte muß dabei dem Divisor entsprechen, damit die resultierende integrierte Leistung unverändert bleibt.The average value of the table values must be equal to the divisor, so that the resulting integrated power remains unchanged.

Bei 10%iger Modulation mit 125 Hz ergeben sich die Tabellenwerte zu
256, 274, 282, 274, 256, 238, 230, 238.At 10% modulation at 125 Hz, the table values increase
256, 274, 282, 274, 256, 238, 230, 238.

Die Auflösung, d. h. die Zahl der Tabellenwerte pro Zeiteinheit ist dadurch veränderbar, daß eine andere Basis genommen wird.The resolution, d. H. the number of table values per time unit can be changed by taking a different basis.

Dieses Ansteuer- bzw. Modulationsverfahren weist den Vorteil auf, daß nur Verschiebe- und Multiplikationsbefehle erforderlich sind, wenn der Divisor eine Zahl mit der Basis 2 ist.This driving or modulation method has the advantage that only shift and multiply instructions are required when the divisor is a base 2 number.

Die Erfindung wurde zuvor anhand bevorzugter Ausführungsbeispiele erläutert. Dem Fachmann sind jedoch Ausgestaltungen und Abwandlungen möglich, ohne daß dadurch der Erfindungsgedanke verlassen wird. Das erfindungsgemäße Verfahren ist insbesondere auch im Zusammenhang mit anderen Vorrichtungen oder Meßverfahren als dem zuvor beschriebenen mit Vorteil einsetzbar, um mit einfachen Mitteln zuverlässige, reproduzierbare Meßergebnisse zu erhalten und daraus die Temperatur, die Transmissivität, die Emissivität und/oder die Reflektivität von Gegenständen mit hoher Genauigkeit zu ermitteln. Das erfindungsgemäße Verfahren ist auch mit anderen Detektoren als dem dargestellten und beschriebenen Lampenpyrometer einsetzbar. So kann z. B. statt des Lampenpyrometers ein Temperatursensor, wie z. B. ein Thermoelement verwendet werden, um die von den Lampen emittierte Strahlung zu ermitteln. Ferner ist es möglich, die von den Lampen emittierte Strahlung mittels einer Impedanzmessung des Lampenfilaments und nachfolgende Verarbeitung des gemessenen Werts zu ermitteln. Anhand einer Impedanz-Intensitäts-Relation der Lampe kann auf die von der Lampe abgestrahlte Intensität zurückgeschlossen werden.The invention has been explained above with reference to preferred embodiments. However, embodiments and modifications are possible for the person skilled in the art without departing from the inventive idea. The method according to the invention is in particular also associated with devices or measuring methods other than those described above can be used with advantage in order to obtain reliable, reproducible measurement results with simple means and to determine therefrom the temperature, the transmissivity, the emissivity and / or the reflectivity of objects with high accuracy. The method according to the invention can also be used with other detectors than the illustrated and described lamp pyrometer. So z. B. instead of the lamp pyrometer, a temperature sensor, such. B. a thermocouple can be used to determine the emitted radiation from the lamps. Furthermore, it is possible to determine the radiation emitted by the lamps by means of an impedance measurement of the lamp filament and subsequent processing of the measured value. Based on an impedance-intensity relation of the lamp can be deduced the intensity emitted by the lamp.

Claims (36)

  1. Method of measuring electromagnetic radiation that is radiated from a surface of an object (2) that is irradiated by electromagnetic radiation given off by at least one radiation source (4, 5), whereby the radiation given off by the radiation source (4, 5) is determined by at least one first detector (7) and the radiation given off by the irradiated object (2) is determined by at least one second detector (6) that measures the radiation, and whereby the radiation from at least one radiation source (4, 5) is actively modulated with at least one characteristic parameter, and the radiation determined by the second detector (6) is corrected with the radiation determined by the first detector (7) characterized in that the characteristic parameter is non-periodically modulated.
  2. Method according to claim 1, characterized in that the active modulation of radiation given off by the radiation source (4, 5), for the characterization thereof, is used during the correction of the radiation determined by the second detector (6).
  3. Method according to claim 1 or 2, characterized in that the radiation given off from at least one radiation source (4, 5) is amplitude, frequency and/or phase modulated.
  4. Method according to one of the proceding claims, characterized in that the signal shape during an amplitude modulation has a continuous signal pattern.
  5. Method according to one of the preceding claims, characterized in that the radiation source (4, 5) comprises a plurality of lamps.
  6. Method according to claim 5, characterized in that the lamps emit their radiation from at least one filament having an at least partially coiled filament structure.
  7. A method according to claim 6, characterized in that due to the filament structure of the lamp a predefined geometrical and spectral radiation can be achieved.
  8. Method according to claim 6 or 7, characterized in that the lamp radiation is emitted from filament sections having alternating coiled and uncoiled filament structure.
  9. Method according to one of the claims 6 to 8, characterized in that the lamp radiation is emitted from two individually controllable filaments.
  10. Method according to one of the claims 6 to 9, characterized in that the lamp radiation is emitted from a filament having at least three electrical connections.
  11. Method according to one of the claims 6 to 10, characterized in that the density of the filament structure varies along the filament.
  12. Method according to one of the preceding claims, characterized in that the radiation is emitted from a halogen lamp.
  13. Method according to one of the preceding claims 1 to 11, characterized in that at least a portion of the radiation is emitted from arc lamps.
  14. Method according to one of the claims 5 to 13, characterized in that the radiation of at least one of the lamps is modulated.
  15. Method according to one of the claims 5 to 14, characterized in that all of the lamps have the same radiation modulation.
  16. Method according to one of the claims 5 to 14, characterized in that the lamps have different radiation modulations.
  17. Method according to one of the claims 14 to 16, characterized in that the radiation modulation for at least some of the lamps is effected synchronously over time.
  18. Method according to one of the preceding claims, characterized in that the degree or depth of modulation of the radiation given off by the radiation source (4, 5) is independent of the radiated lamp intensity.
  19. Method according to one of the preceding claims, characterized in that the degree or depth of modulation is dependent upon the radiated lamp intensity.
  20. Method according to one of the preceding claims, characterized in that the degree or depth of modulation is controlled.
  21. Method according to one of the preceding claims, characterized in that the lamp intensity is pulse width modulated.
  22. Method according to one of the preceding claims, characterized in that the radiation is modulated with a data processing program by using tabular values.
  23. Method according to one of the claims 1 to 21, characterized in that the radiation is modulated for the pulse width modulation by altering the register frequency of generators.
  24. Method according to one of the preceding claims, characterized in that the radiation given off by the radiation source (4, 5) is modulated by a modulation of the control signals for the radiation source or sources.
  25. Method according to one of the preceding claims, characterized by the use to determine the temperature, reflectivity, transmissivity and/or emissivity of an object.
  26. Method according to one of the preceding claims, characterized by the use in conjunction with the thermal treatment of semiconductor substrates (2).
  27. Method according to claim 26, characterized in that the thermal treatment of the semiconductor substrate (2) is effected within a reaction chamber (3) that essentially comprises a material that is transparent for the electromagnetic radiation of the radiation sources (4, 5) and for the spectrum of the measurement wavelengths of the detectors (6, 7)
  28. Method according to claim 27, characterized in that the transparent material comprises quartz glass and/or sapphire.
  29. Method according to claim 27 or 28, characterized in that the material has an absorption coefficient that is averaged over the lamp spectrum and is between 0.001 cm-1 and 0.1 cm-1.
  30. Method according to claim 27 to 29, characterized in that the radiation of the radiation source (4, 5) is transmitted through a reaction chamber (3) wall thickness between 1 mm and 5 cm.
  31. Method according to one of the preceding claims, characterized, in that the first detector (7) is a radiation detector.
  32. Method according to claim 31, characterized in that the first detector (7) receives the radiation given off by the radiation source (4, 5) via optical lines or light channels.
  33. Method according to claim 32, characterized in that by means of an arrangement of the radiation source (4, 5) and the optical lines or the light channels relative to one another, the first radiation detector (7) generates a signal that is free of influences from filament holding mechanisms or other means that adversely affect the radiation flux or the radiation temperature of the radiation source (4, 5).
  34. Method according to one of the claims 1 to 31, characterized in that the first detector (7) is a temperature sensor.
  35. Method according to one the claims 1 to 30, characterized in that the first detector (7) measures a parameter that is related to the radiation given off by the radiation sources (4, 5).
  36. Method according to claim 35, characterized in that the detector (7) measures the impedance of the radiation sources (4, 5).
EP98123129A 1997-12-08 1998-12-04 Method for the measurement of electromagnetic radiation Expired - Lifetime EP0924500B1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9121771B2 (en) 2010-03-16 2015-09-01 The Penn State Research Foundation Methods and apparatus for ultra-sensitive temperature detection using resonant devices

Families Citing this family (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19964181B4 (en) * 1999-02-10 2005-12-08 Steag Rtp Systems Gmbh Apparatus for measuring the temperature of substrates
US6331212B1 (en) * 2000-04-17 2001-12-18 Avansys, Llc Methods and apparatus for thermally processing wafers
US6799137B2 (en) * 2000-06-02 2004-09-28 Engelhard Corporation Wafer temperature measurement method for plasma environments
US6465761B2 (en) * 2000-07-24 2002-10-15 Asm America, Inc. Heat lamps for zone heating
JP2002118071A (en) * 2000-10-10 2002-04-19 Ushio Inc Apparatus and method for heat treatment by light irradiation
DE10051125A1 (en) * 2000-10-16 2002-05-02 Steag Rtp Systems Gmbh Device for the thermal treatment of substrates
US6707011B2 (en) 2001-04-17 2004-03-16 Mattson Technology, Inc. Rapid thermal processing system for integrated circuits
DE10222879A1 (en) * 2001-05-23 2005-03-17 Mattson Thermal Products Gmbh Measurement of low wafer temperatures
US6917039B2 (en) * 2002-02-13 2005-07-12 Therma-Wave, Inc. Method and system for combined photothermal modulated reflectance and photothermal IR radiometric system
US6849831B2 (en) * 2002-03-29 2005-02-01 Mattson Technology, Inc. Pulsed processing semiconductor heating methods using combinations of heating sources
US7734439B2 (en) 2002-06-24 2010-06-08 Mattson Technology, Inc. System and process for calibrating pyrometers in thermal processing chambers
US7412299B2 (en) * 2002-12-23 2008-08-12 Mattson Thermal Products Gmbh Process for determining the temperature of a semiconductor wafer in a rapid heating unit
DE10329107B4 (en) * 2002-12-23 2015-05-28 Mattson Thermal Products Gmbh Method for determining at least one state variable from a model of an RTP system
JP4618705B2 (en) * 2003-09-18 2011-01-26 大日本スクリーン製造株式会社 Heat treatment equipment
US7514686B2 (en) * 2004-08-10 2009-04-07 Canon Kabushiki Kaisha Radiation detecting apparatus, scintillator panel, their manufacturing method and radiation detecting system
CN1828829A (en) * 2005-03-02 2006-09-06 优志旺电机株式会社 Heater and heating device with heaters
WO2007005489A2 (en) * 2005-07-05 2007-01-11 Mattson Technology, Inc. Method and system for determining optical properties of semiconductor wafers
DE102006019807B3 (en) * 2006-04-21 2007-08-23 Leibnitz-Institut für Festkörper- und Werkstoffforschung Dresden e.V. Pyrometric measurement of temperature or temperature distribution of a melt in crystal growth plants, comprises heating the melt area by infrared radiation sources and interrupting the effect of the radiation sources on the melt area
US7543981B2 (en) 2006-06-29 2009-06-09 Mattson Technology, Inc. Methods for determining wafer temperature
DE102006036585B4 (en) * 2006-08-04 2008-04-17 Mattson Thermal Products Gmbh Method and device for determining measured values
US7976216B2 (en) * 2007-12-20 2011-07-12 Mattson Technology, Inc. Determining the temperature of silicon at high temperatures
KR101819636B1 (en) * 2009-12-23 2018-01-17 헤라우스 노블라이트 아메리카 엘엘씨 Uv led based lamp for compact uv curing lamp assemblies
TWM413957U (en) * 2010-10-27 2011-10-11 Tangteck Equipment Inc Diffusion furnace apparatus
DE102011116243B4 (en) * 2011-10-17 2014-04-17 Centrotherm Photovoltaics Ag Device for determining the temperature of a substrate
US9159597B2 (en) * 2012-05-15 2015-10-13 Taiwan Semiconductor Manufacturing Company, Ltd. Real-time calibration for wafer processing chamber lamp modules
KR20240007688A (en) * 2018-06-26 2024-01-16 어플라이드 머티어리얼스, 인코포레이티드 Method and apparatus for measuring temperature
US11032945B2 (en) * 2019-07-12 2021-06-08 Applied Materials, Inc. Heat shield assembly for an epitaxy chamber
TW202200989A (en) * 2020-03-13 2022-01-01 美商應用材料股份有限公司 Apparatus and method for inspecting lamps

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8316306D0 (en) * 1983-06-15 1983-07-20 Thorn Emi Domestic Appliances Heating apparatus
US4680451A (en) * 1985-07-29 1987-07-14 A. G. Associates Apparatus using high intensity CW lamps for improved heat treating of semiconductor wafers
US4818102A (en) 1986-12-22 1989-04-04 United Technologies Corporation Active optical pyrometer
US5310260A (en) 1990-04-10 1994-05-10 Luxtron Corporation Non-contact optical techniques for measuring surface conditions
US5154512A (en) * 1990-04-10 1992-10-13 Luxtron Corporation Non-contact techniques for measuring temperature or radiation-heated objects
DE69207965T2 (en) * 1991-07-08 1996-08-22 Philips Electronics Nv Electrical food preparation apparatus and electric lamp for use in this apparatus
US5180226A (en) * 1991-10-30 1993-01-19 Texas Instruments Incorporated Method and apparatus for precise temperature measurement
NL9201155A (en) * 1992-06-29 1994-01-17 Imec Inter Uni Micro Electr DEVICE AND METHOD FOR HEATING OBJECTS MEASURING THE TEMPERATURE OF THE ARTICLE
US5714392A (en) * 1996-07-26 1998-02-03 Advanced Micro Devices, Inc. Rapid thermal anneal system and method including improved temperature sensing and monitoring

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9121771B2 (en) 2010-03-16 2015-09-01 The Penn State Research Foundation Methods and apparatus for ultra-sensitive temperature detection using resonant devices
US10184845B2 (en) 2010-03-16 2019-01-22 The Penn State Research Foundation Methods and apparatus for ultra-sensitive temperature detection using resonant devices

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US20010010308A1 (en) 2001-08-02
DE59813773D1 (en) 2006-11-30
EP0924500A3 (en) 2001-04-04
SG71178A1 (en) 2003-08-20
JP3403099B2 (en) 2003-05-06
US6191392B1 (en) 2001-02-20
US6369363B2 (en) 2002-04-09
JPH11237281A (en) 1999-08-31

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